Conventionally, facsimile machines and photocopying machines are provided with an image reading apparatus for reading a document as image information.
Examples of such image reading apparatus include an image reading apparatus that carries out reading in one of a fed document reading mode and a stationary document reading mode, which are switched over according to a need, where reading means for reading is fixedly-positioned to read a fed-in document in the fed document reading mode, while the reading means is moved to read a stationary document in the stationary document reading mode.
For example, Japanese Unexamined Patent Publication, Tokukaihei, No. 6-268790 (Publication date: Sep. 22, 1994) (Conventional Art 1) discloses a “facsimile machine” that reads a cut-sheet type of document (sheet type of document), which can be separated sheet by sheet, and a book type of document, such as a spread-book document (document of a book spread), which cannot be separated sheet by sheet.
The facsimile machine carries out reading in one of a fed document reading mode and a stationary document reading mode, which are switched over according to a need. In the fed document reading mode, the cut-sheet type of document is read by a fixedly-positioned reading unit (reading means) while the cut-sheet type of document is fed in by a document feeder. In the stationary document reading mode, the book type of document or the cut-sheet type of document is placed (is still placed (being stationary)) on a document platform, and is read by the reading unit, which is being moved to read.
However, the image reading apparatus of the facsimile apparatus that is disclosed in the Conventional Art 1 provided with separate driving force sources (motors); (a) a driving force source (motor) for supplying a driving force to the feeder, which is used in the fed document reading mode, and (b) a driving force source (motor) for supplying a driving force to the reading unit, which is being moved to read, in the stationary document reading mode. For this reason, it is necessary to provide the image reading apparatus with separate systems for supplying the driving forces from the motors to the driving force sources, respectively. This complicates a whole apparatus, thus arising problems that the apparatus has a large size and a high cost.
In view of this, Japanese Unexamined Patent Publication, Tokukaihei, No. 1-266529 (Publication Date: Oct. 24, 1989) (Conventional Art 2), discloses an art in which a driving motor is used both as a driving force source (motor) for supplying a driving force to a feeder used in the fed document reading mode, and as a driving force source (motor) for supplying a driving force to a reading unit that is moved in the stationary document reading mode.
With this arrangement, in which the same driving force source (motor) supplies the driving force required in the fed document reading mode and stationary document reading mode, it is possible to simplify a system to transmit the driving force. As a result, the whole apparatus can be miniaturized.
In the art disclosed in the Conventional Art 2, however, a solenoid or an electromagnetic clutch, which is high in cost, is used to switch over (change over) the driving force for the feeder used in the fed document reading mode and the driving force for the reading unit that is moved in the stationary document reading mode. The high cost of those members increases the cost of the whole apparatus.